CN115770878A - A method for reducing the anisotropy of the mechanical properties of additively manufactured high-strength titanium alloys - Google Patents

Abstract

The invention discloses a method for reducing anisotropy of mechanical properties of high-strength titanium alloy manufactured by additive manufacturing, which comprises the following steps: 1. adding iron powder into the spherical Ti185 alloy powder and ball-milling to obtain mixed powder; 2. drawing a three-dimensional model of a target product and carrying out layering processing to obtain slicing data and design slicing scanning data; 3. importing the layer cutting data and the layer cutting scanning data into equipment for powder filling, leveling a forming bottom plate and preheating; 4. laying and laying a powder layer and preheating; 5. melting and scanning to form a single-layer solid sheet layer; 6. and repeating the processes to form a powder bed electron beam additive manufacturing forming piece to obtain the high-strength titanium alloy. According to the invention, the powder bed electron beam additive manufacturing is carried out by adding the iron powder into the Ti185 alloy powder, so that the growth restriction factor and the solidification temperature interval value of the alloy are improved, the formation of equiaxed crystals in the titanium alloy is facilitated, the strength of the titanium alloy is improved, the anisotropy of the mechanical property of the titanium alloy is reduced, and the titanium alloy is used as a high-strength component and has a wide application range.

Description

A method to reduce the anisotropy of the mechanical properties of additively manufactured high-strength titanium alloys

technical field

The invention belongs to the technical field of alloy material preparation, and in particular relates to a method for reducing the anisotropy of the mechanical properties of a high-strength titanium alloy manufactured by additive manufacturing.

Background technique

Titanium alloy has the advantages of high specific strength, good biocompatibility, corrosion resistance, non-magnetism, heat resistance, etc., and has been widely used in biomedical, aerospace, marine engineering, petrochemical and other fields. With the rapid development of the aerospace industry, conventional titanium alloy materials are difficult to meet its needs, so high-strength titanium alloys have entered people's sight.

Titanium alloys have many difficulties in the preparation of titanium alloy samples due to their poor thermal conductivity, high deformation resistance, narrow forging temperature range, and high affinity for oxygen. Powder bed electron beam additive manufacturing, also known as electron beam selective melting (SEBM), is an advanced manufacturing technology developed in the 1990s. It has the advantages of fast scanning speed, no pollution in high vacuum environment, and low residual stress. It is especially suitable for titanium Direct forming of active metal materials such as alloys.

Ti-1Al-8V-5Fe (Ti185) alloy is a metastable β-titanium alloy with high tensile strength and shear strength. It is widely used in aerospace fasteners and some components that require high strength. In addition, the alloy is less costly than other metastable β-titanium alloys. However, powder bed electron beam additive manufacturing is used to form Ti185 alloy. The interior of the alloy is a coarse columnar grain structure along the forming direction, resulting in obvious anisotropy of the mechanical properties of the alloy. This problem seriously restricts powder bed electron beam additive manufacturing and its preparation of titanium alloys. Large-scale development and promotion of applications.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for reducing the anisotropy of the mechanical properties of high-strength titanium alloys manufactured by additive manufacturing in view of the above-mentioned deficiencies in the prior art. The method prepares titanium alloy by adding iron powder to Ti185 alloy powder for powder bed electron beam additive manufacturing, which improves the growth limiting factor and solidification temperature interval value of the alloy, is beneficial to the formation of equiaxed crystals in titanium alloy, and reduces β/α at the same time The transition temperature promotes the precipitation of nano-α strengthening phase of titanium alloy, thereby improving the strength of titanium alloy and reducing the anisotropy of mechanical properties of titanium alloy.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a method for reducing the anisotropy of the mechanical properties of high-strength titanium alloys manufactured by additive manufacturing, which is characterized in that, by increasing the Ti-1Al-8V-5Fe alloy, that is, the Ti185 alloy powder The iron content in the powder bed electron beam additive manufacturing is used to prepare a high-strength titanium alloy with isotropic mechanical properties. The method includes the following steps:

Step 1. Add iron powder to the spherical Ti185 alloy powder prepared by plasma rotating electrode gas atomization, and then use a planetary ball mill to perform ball milling to obtain a mixed powder;

Step 2. Draw the 3D model of the target product titanium alloy, and then perform layering processing, cut into slices of equal thickness along the height direction of the 3D model, and obtain the slice data, and then scan the internal scanning method and scan of each slice Design the path and obtain slice scanning data;

Step 3. Import the slice data and slice scan data obtained in step 2 into the powder bed electron beam additive manufacturing forming equipment, and put the mixed powder obtained in step 1 into the powder box of the powder bed electron beam additive manufacturing equipment , and then level the forming base plate and preheat the forming base plate, the preheating temperature of the forming base plate is 700 ° C ~ 720 ° C;

Step 4. Lay the mixed powder loaded into the powder box in step 3 on the preheated forming bottom plate to form a powder layer, and then preheat the powder layer. The preheating temperature of the powder layer is 700°C to 720°C. ℃; the thickness of the powder layer is the same as the thickness of the cut sheet in step 3;

Step 5. According to the slice data and slice scan data imported into the powder bed electron beam additive manufacturing forming equipment in step 3, the electron beam is used to melt and scan the preheated powder layer in step 4 to form a single layer Solid sheet, then the forming bottom plate is lowered, and the lowering height of the forming bottom plate is the same as the thickness of the sheet layer cut in step 4;

Step 6. Repeat the powder spreading process and preheating process in step 4 and the melting scanning process and forming base plate lowering process in step 5 until each single-layer solid sheet is piled up layer by layer to form a powder bed electron beam additive manufacturing shaped part , and then take it out when the temperature of the forming bottom plate is less than 100°C, use high-pressure gas to remove the residual powder on the surface of the formed part by powder bed electron beam additive manufacturing, and obtain a high-strength titanium alloy; the tensile strength of the high-strength titanium alloy in the horizontal direction is higher than 1317MPa , the tensile strength in the vertical direction is higher than 1303MPa, the tensile yield strength in the horizontal direction is higher than 1241MPa, the tensile yield strength in the vertical direction is higher than 1222MPa, the elongation after fracture is higher than 5%, and the strength anisotropy value is not higher than 1.5.

The invention uses the spherical Ti185 alloy powder prepared by gas atomization of a plasma rotating electrode as a raw material, adds iron powder for ball milling and mixing to obtain a mixed powder, and then prepares a high-strength titanium alloy with isotropic mechanical properties through powder bed electron beam additive manufacturing. First of all, the spherical Ti185 alloy powder prepared by plasma rotating electrode gas atomization adopted in the present invention has high sphericity, and the particle size is suitable for powder bed electron beam additive manufacturing equipment. Improve the uniformity of the structure of the Ti185 alloy; secondly, the present invention increases the growth limiting factor and the solidification temperature range of the alloy by adding iron powder to the spherical Ti185 alloy powder, which is beneficial to the formation of equiaxed crystals. At the same time, iron is β-stable Elements, the increase of iron content reduces the β/α transition temperature of the alloy, and the preparation combined with powder bed electron beam additive manufacturing is conducive to obtaining a finer strengthening phase α for the titanium alloy, which reduces the anisotropy of the mechanical properties of the titanium alloy; And spherical Ti185 alloy powder and iron powder adopt planetary ball mill to carry out ball milling and mixing, help iron powder to be evenly distributed on the surface of Ti185 alloy powder, help to improve the component uniformity of product titanium alloy; Again, powder bed electron beam of the present invention In the process of additive manufacturing, by preheating the forming base plate and powder layer, and controlling the preheating temperature at 700°C to 720°C, each single-layer solid sheet is subjected to repeated heat treatment, which is beneficial to the production of titanium. The internal thermal stress of the alloy is gradually released, and then the internal structure of the titanium alloy tends to be uniform. At the same time, the spherical Ti185 alloy powder in the powder layer is preheated and then melted and scanned to make the powders stick together and avoid the movement of the powder layer caused by the impact of the electron beam. The interlayer bonding force of the titanium alloy is improved, and the composition segregation of the titanium alloy is avoided, especially the segregation of the Fe element produces β spot defects, which affects the strength of the titanium alloy.

The above-mentioned method for reducing the anisotropy of the mechanical properties of high-strength titanium alloys by additive manufacturing is characterized in that the spherical Ti185 alloy powder in step 1 is composed of the following components by mass content: Al 1.38%, V 8.00%, Fe4. 22%, O 0.19%, the balance is titanium and unavoidable impurities, and the particle size of the spherical Ti185 alloy powder is 40 μm to 150 μm. The spherical Ti185 alloy powder with this particle size has good fluidity, which is conducive to the spreading of the mixed powder on the forming base plate, improves the uniformity of the powder layer, and then improves the uniformity of each component in the product titanium alloy, avoiding the occurrence of component Segregation phenomenon; at the same time, the spherical Ti185 alloy powder with this particle size is conducive to improving its melting speed in the forming process of powder bed electron beam additive manufacturing.

The aforementioned method for reducing the anisotropy of the mechanical properties of high-strength titanium alloys by additive manufacturing is characterized in that the particle size of the iron powder in step 1 is 1 μm, and the addition amount is 1.89% of the mass of the spherical Ti185 alloy powder. By controlling the particle size of the iron powder, it is beneficial for the iron powder to evenly adhere to the surface of the Ti185 alloy powder without agglomeration. Usually, the iron mass content of the Ti185 alloy is 4% to 6%. According to the calculation method of the chemical element ratio, 1.89% iron powder is added to the Ti185 alloy powder of the present invention to prepare a mixed powder. The iron content in the mixed powder is still the same as that of the conventional Ti185 alloy Within the range of the composition content of the powder, the introduction of other impurity elements is avoided, which is conducive to ensuring the mechanical properties of the titanium alloy.

The ball milling process of the present invention is as follows: add iron powder to the spherical Ti185 alloy powder prepared by plasma rotating electrode gas atomization, then put it into the ball milling jar of the planetary ball mill, and add ball milling beads and ethanol in the ball milling jar, at 20r/ The ball milling was carried out for 4 hours at a rotational speed of 1 min to obtain a mixed powder. During this process, ethanol was added to promote the uniform attachment of the iron powder on the surface of the spherical Ti185 alloy powder.

The above-mentioned method for reducing the anisotropy of mechanical properties of high-strength titanium alloys manufactured by additive manufacturing is characterized in that the thickness of the equal-thickness sheet described in step 2 is 0.1 mm. By controlling the thickness of the sheet to 0.1mm, it is suitable for the melting ability of the electron beam to the mixed powder.

The above-mentioned method for reducing the anisotropy of the mechanical properties of high-strength titanium alloys by additive manufacturing is characterized in that the process parameters of the melting scan described in step five are: scan line spacing 0.1mm, scan current 15mA, scan speed 3300mm/s . Using the above melting and scanning forming parameters to carry out powder bed electron beam additive manufacturing of titanium alloy spherical powder to titanium alloy, effectively control the dimensional accuracy and melting quality of each layer in the forming process, so that the prepared titanium alloy formed parts are uniform inside and complete in shape , which is beneficial to improve the strength of titanium alloy.

Compared with the prior art, the present invention has the following advantages:

1. The present invention prepares titanium alloy by adding iron powder to Ti185 alloy powder for powder bed electron beam additive manufacturing, which improves the growth limiting factor and solidification temperature interval value of the alloy, is conducive to the formation of equiaxed crystals in titanium alloy, and reduces β at the same time /α transition temperature, promotes the precipitation of nano-α strengthening phase of titanium alloy, thereby improving the strength of titanium alloy and reducing the anisotropy of mechanical properties of titanium alloy.

2. The present invention not only promotes the formation of equiaxed crystals in the titanium alloy by adding iron powder to the Ti185 alloy powder and controlling the addition amount according to the calculation method of the chemical element ratio, but also the iron content in the mixed powder after the addition is still lower than that of the conventional Ti185 alloy Within the range of the composition content of the powder, the introduction of other impurity elements is avoided, which is conducive to ensuring the mechanical properties of the titanium alloy.

3. In the powder bed electron beam additive manufacturing process of the present invention, by preheating the powder layer and the forming bottom plate, it is beneficial to gradually release the internal thermal stress of the product titanium alloy, and then the internal structure of the titanium alloy tends to be uniform, while avoiding Inter-adhesion improves the bonding force between titanium alloy layers and avoids component segregation, further ensuring the strength and other mechanical properties of titanium alloys.

4. The present invention combines iron powder with powder bed electron beam additive manufacturing, so that the interior of the prepared titanium alloy is equiaxed, has high strength and significantly reduces the anisotropy of mechanical properties, and the tensile strength in the horizontal direction is higher than 1317MPa. The tensile strength in the vertical direction is higher than 1303MPa, the tensile yield strength in the horizontal direction is higher than 1241MPa, the tensile yield strength in the vertical direction is higher than 1222MPa, the elongation after fracture is higher than 5%, and the strength anisotropy value is not high More than 1.5, it can be made into high-strength parts and has a wide range of applications.

The technical solutions of the present invention will be described in further detail below with reference to the drawings and embodiments.

Description of drawings

FIG. 1 is an optical micrograph of the titanium alloy prepared in Example 1 of the present invention.

FIG. 2 is an optical microscope image of the titanium alloy prepared in Comparative Example 1 of the present invention.

Detailed ways

The powder bed electron beam additive manufacturing equipment used in Examples 1-2 of the present invention and Comparative Examples 1-2 is Sialon Y150 type.

Example 1

This embodiment includes the following steps:

Step 1. Put 1 kg of spherical Ti185 alloy powder prepared by gas atomization with a plasma rotating electrode with a particle size of 40 μm to 150 μm into the ball mill tank, then add 18.9 g of iron powder with a particle size of 1 μm, then add ball milling beads and ethanol, and use a planetary method The ball mill was milled for 4 hours at a rotating speed of 20r/min to obtain a mixed powder; the spherical Ti185 alloy powder was composed of the following components by mass: Al 1.38%, V 8.00%, Fe 4.22%, O 0.19%, and the balance was Titanium and unavoidable impurities;

Step 2. Use Magics software to draw a three-dimensional model of the target product titanium alloy. The size of the model is 80mm×13mm×22mm (length×width×height), and then carry out layering processing, and cut it into pieces with a thickness of 0.1mm along the height direction of the three-dimensional model slices of equal thickness, and obtain slice data, and then design the internal scanning mode and scan path of each slice to obtain slice scan data; the slice scan data includes: the scan line spacing is 0.1mm, the scan The current is 15mA, and the scanning speed is 3300mm/s;

Step 3. Import the slice data and slice scan data obtained in step 2 into the powder bed electron beam additive manufacturing forming equipment, and put 8kg of the mixed powder obtained in step 1 into the powder box of the powder bed electron beam additive manufacturing equipment , then level the forming base plate and preheat the forming base plate, the preheating temperature of the forming base plate is 720°C, and the size of the forming base plate is 100mm×100mm×10mm (length×width×thick);

Step 4. Lay the mixed powder loaded into the powder box in step 3 on the preheated forming base plate to form a powder layer with a thickness of 0.1mm, and then preheat the powder layer. The preheating temperature of the powder layer is 720°C;

Step 5. According to the slice data and slice scan data imported into the powder bed electron beam additive manufacturing forming equipment in step 3, the electron beam is used to melt and scan the preheated powder layer in step 4 to form a single layer Solid sheet, and then lower the forming base plate by 0.1mm; the process parameters of the melting scan are: scan line spacing 0.1mm, scan current 15mA, scan speed 3300mm/s;

Step 6. Repeat the powder spreading process and preheating process in step 4 and the melting scanning process and forming base plate lowering process in step 5 until each single-layer solid sheet is piled up layer by layer to form a powder bed electron beam additive manufacturing shaped part , and then take it out when the temperature of the formed bottom plate is less than 100°C, and use high-pressure gas to remove the residual powder on the surface of the formed part manufactured by powder bed electron beam additive manufacturing to obtain a high-strength titanium alloy.

After testing, the horizontal tensile strength of the high-strength titanium alloy prepared in this embodiment is 1336MPa, the tensile yield strength is 1270MPa, the elongation after fracture is 9%, the vertical tensile strength is 1366MPa, and the tensile yield strength is 1256MPa, the elongation after fracture is 6%, the anisotropy of tensile strength is 1.4, and the anisotropy of tensile yield strength is 1.1. Among them, the anisotropic value (IPA) is calculated according to formula (1).

In formula (1), T _H represents the tensile or yield strength of the sample in the horizontal direction, in MPa; T _V represents the tensile or yield strength of the sample in the vertical direction, in MPa.

Figure 1 is an optical microscope image of the titanium alloy prepared in this example. It can be seen from Figure 1 that the titanium alloy is equiaxed along the forming direction and has a fine α phase inside.

Comparative example 1

The difference between this comparative example and Example 1 is that this comparative example does not have Step 1, that is, no iron powder is added to Ti185 alloy powder to obtain Ti185 alloy.

After testing, the horizontal tensile strength of the Ti185 alloy prepared in this comparative example is 1075MPa, the tensile yield strength is 1005MPa, the elongation after fracture is 17%, the vertical tensile strength is 1131MPa, and the tensile yield strength is 1059MPa , The elongation after breaking is 6%, the anisotropy value of the tensile strength is 5.1, and the anisotropy value of the tensile yield strength is 5.2.

FIG. 2 is an optical microscope image of the titanium alloy prepared in this comparative example. It can be seen from FIG. 2 that the titanium alloy has a columnar grain structure along the forming direction.

Comparing Example 1 with Comparative Example 1, it can be seen that the growth limiting factor and solidification temperature range of the Ti185 alloy powder not mixed with iron powder in Comparative Example 1 are relatively low. After calculation, the Ti185 alloy (iron mass content is 4.22%) The growth limiting factor is 46.8, and the solidification temperature interval value is 96 ° C; while adding 1.89% iron powder to the Ti185 alloy powder in Example 1 to form a mixed titanium alloy powder, the growth limiting factor of the titanium alloy (iron mass content is 6%) is 66.6, and the solidification temperature range is 129°C. According to the interdependence theory of solidification, the higher the value of the growth limiting factor and the solidification temperature range, the easier it is to form equiaxed crystals. Therefore, the interior of the titanium alloy obtained in Example 1 is equiaxed crystals, while the interior of the titanium alloy obtained in Comparative Example 1 is columnar crystals, and the grain size of the equiaxed crystals and the size of the intragranular strengthening phase are smaller than the corresponding columnar crystals, resulting in The former is stronger than the latter.

Comparative example 2

The difference between this comparative example and Example 1 is that the amount of iron powder added in step 1 of this comparative example is 41.1 g, and the mass content of iron in the titanium alloy is 8%.

In the forming process of powder bed electron beam additive manufacturing in this comparative example, the powder fluidity is poor and a large amount of splash is generated during the forming process, which leads to the termination of the forming process.

Comparing Example 1 with Comparative Example 2, it can be seen that the amount of iron powder added in Comparative Example 2 is 4.11%, and the iron mass content in the titanium alloy is as high as 8%. Because the iron powder content is too high, the sphericity of the mixed powder becomes poor, thus flowing reduced sex. At the same time, due to the difference between the melting point of iron and the melting point of Ti185 alloy by more than 100 °C, when the mass content of iron powder increases, a large amount of spatter will be generated when powder bed electron beam additive manufacturing technology is used to form, which seriously affects the performance of the formed part and leads to the formation process fail.

In summary, the present invention increases the growth limiting factor and the solidification temperature interval value of the alloy by adding iron powder to the Ti185 alloy powder and controlling the amount of iron powder added to 6%. At the same time, the mixed powder has good fluidity, ensuring the smoothness of the forming process. and promote the formation of equiaxed grains in titanium alloys, thereby improving the strength of titanium alloys.

Example 2

This embodiment includes the following steps:

Step 1. Put 1 kg of spherical Ti185 alloy powder prepared by gas atomization with a plasma rotating electrode with a particle size of 40 μm to 150 μm into the ball mill tank, then add 18.9 g of iron powder with a particle size of 1 μm, then add ball milling beads and ethanol, and use a planetary method The ball mill was milled for 4 hours at a rotating speed of 20r/min to obtain a mixed powder; the spherical Ti185 alloy powder was composed of the following components by mass: Al 1.38%, V 8.00%, Fe 4.22%, O 0.19%, and the balance was Titanium and unavoidable impurities;

Step 2. Use Magics software to draw a three-dimensional model of the target product titanium alloy. The size of the model is 80mm×13mm×22mm (length×width×height), and then carry out layering processing, and cut it into pieces with a thickness of 0.1mm along the height direction of the three-dimensional model slices of equal thickness, and obtain slice data, and then design the internal scanning mode and scan path of each slice to obtain slice scan data; the slice scan data includes: the scan line spacing is 0.1mm, the scan The current is 15mA, and the scanning speed is 3300mm/s;

Step 3. Import the slice data and slice scan data obtained in step 2 into the powder bed electron beam additive manufacturing forming equipment, and put 8kg of the mixed powder obtained in step 1 into the powder box of the powder bed electron beam additive manufacturing equipment , then level the forming base plate and preheat the forming base plate, the preheating temperature of the forming base plate is 700°C, and the size of the forming base plate is 100mm×100mm×10mm (length×width×thick);

Step 4. Lay the mixed powder loaded into the powder box in step 3 on the preheated forming base plate to form a powder layer with a thickness of 0.1mm, and then preheat the powder layer. The preheating temperature of the powder layer is 700°C;

Step 5. According to the slice data and slice scan data imported into the powder bed electron beam additive manufacturing forming equipment in step 3, the electron beam is used to melt and scan the preheated powder layer in step 4 to form a single layer Solid sheet, and then lower the forming base plate by 0.1mm; the process parameters of the melting scan are: scan line spacing 0.1mm, scan current 15mA, scan speed 3300mm/s;

Step 6. Repeat the powder spreading process and preheating process in step 4 and the melting scanning process and forming base plate lowering process in step 5 until each single-layer solid sheet is piled up layer by layer to form a powder bed electron beam additive manufacturing shaped part , and then take it out when the temperature of the formed bottom plate is less than 100°C, and use high-pressure gas to remove the residual powder on the surface of the formed part manufactured by powder bed electron beam additive manufacturing to obtain a high-strength titanium alloy.

After testing, the tensile strength of the high-strength titanium alloy prepared in this embodiment in the horizontal direction is 1317MPa, the tensile yield strength is 1241MPa, the elongation after fracture is 7%, the tensile strength in the vertical direction is 1303MPa, and the tensile yield strength is 1222MPa, the elongation after fracture is 5%, the anisotropy of tensile strength is 1.1, and the anisotropy of tensile yield strength is 1.5.

The above descriptions are only preferred embodiments of the present invention, and do not limit the present invention in any way. All simple modifications, changes and equivalent changes made to the above embodiments according to the technical essence of the invention still belong to the protection scope of the technical solution of the invention.

Claims (5)

1. A method for reducing anisotropy of mechanical properties of high-strength titanium alloy manufactured by additive manufacturing is characterized in that the high-strength titanium alloy with isotropic mechanical properties is prepared by increasing the iron content in Ti-1Al-8V-5Fe alloy, namely Ti185 alloy powder and adopting powder bed electron beam additive manufacturing, and the method comprises the following steps:

step one, adding iron powder into spherical Ti185 alloy powder prepared by plasma rotating electrode gas atomization, and then carrying out ball milling by adopting a planetary ball mill to obtain mixed powder;

drawing a three-dimensional model of a target product titanium alloy, then carrying out layering treatment, cutting the three-dimensional model into equal-thickness slices along the height direction of the three-dimensional model, obtaining slicing data, and designing the internal scanning mode and scanning path of each slice to obtain slicing scanning data;

step three, guiding the layer cutting data and the layer cutting scanning data obtained in the step two into powder bed electron beam additive manufacturing forming equipment, loading the mixed powder obtained in the step one into a powder box of the powder bed electron beam additive manufacturing equipment, leveling a forming bottom plate and preheating the forming bottom plate, wherein the preheating temperature of the forming bottom plate is 700-720 ℃;

step four, laying the mixed powder loaded into the powder box in the step three on the preheated forming bottom plate to form a powder laying layer, and then preheating the powder laying layer, wherein the preheating temperature of the powder laying layer is 700-720 ℃; the thickness of the powder laying layer is the same as that of the sliced sheet layer in the step three;

step five, according to the layer cutting data and the layer cutting scanning data which are led into the powder bed electron beam additive manufacturing forming equipment in the step three, melting and scanning the preheated powder laying layer in the step four by adopting an electron beam to form a single-layer solid sheet layer, and then descending the forming bottom plate, wherein the descending height of the forming bottom plate is the same as the thickness of the sheet layer which is divided in the step four;

step six, repeating the powder laying process and the preheating process in the step four and the melting scanning process and the forming bottom plate descending process in the step five until all the single-layer solid sheets are stacked layer by layer to form a powder bed electron beam additive manufacturing formed part, taking out the formed bottom plate when the temperature of the formed bottom plate is lower than 100 ℃, and removing residual powder on the surface of the powder bed electron beam additive manufacturing formed part by using high-pressure gas to obtain high-strength titanium alloy; the tensile strength of the high-strength titanium alloy in the horizontal direction is higher than 1317MPa, the tensile strength of the high-strength titanium alloy in the vertical direction is higher than 1303MPa, the tensile yield strength of the high-strength titanium alloy in the horizontal direction is higher than 1241MPa, the tensile yield strength of the high-strength titanium alloy in the vertical direction is higher than 1222MPa, the elongation after fracture is higher than 5%, and the strength anisotropy value is not higher than 1.5.

2. The method for reducing the anisotropy of mechanical properties of the additive manufactured high-strength titanium alloy according to claim 1, wherein in the first step, the spherical Ti185 alloy powder consists of the following components in percentage by mass: 1.38% of Al, 8.00% of V, 4.22% of Fe, 0.19% of O and the balance of titanium and inevitable impurities, and the particle size of the spherical Ti185 alloy powder is 40-150 μm.

3. The method for reducing the anisotropy of mechanical properties of high-strength titanium alloy manufactured by additive manufacturing according to claim 1, wherein the iron powder in the first step has a particle size of 1 μm and is added in an amount of 1.89% of the mass of the spherical Ti185 alloy powder.

4. The method for reducing the anisotropy of mechanical properties of the additive manufactured high-strength titanium alloy according to claim 1, wherein the thickness of the equal-thickness sheet layer in the second step is 0.1mm.

5. The method for reducing anisotropy of mechanical properties of additive manufactured high-strength titanium alloy according to claim 1, wherein the process parameters of the melting scan in the fifth step are as follows: the distance between scanning lines is 0.1mm, the scanning current is 15mA, and the scanning speed is 3300mm/s.

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